<?php
	/**
    This file is part of WideImage.
		
    WideImage is free software; you can redistribute it and/or modify
    it under the terms of the GNU Lesser General Public License as published by
    the Free Software Foundation; either version 2.1 of the License, or
    (at your option) any later version.
		
    WideImage is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU Lesser General Public License for more details.
		
    You should have received a copy of the GNU Lesser General Public License
    along with WideImage; if not, write to the Free Software
    Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
  **/
	
	class wiUnknownImageOperationException extends wiException {}
	
	class wiOpFactory
	{
		static protected $cache = array();
		
		static function get($operationName)
		{
			if (!isset(self::$cache[$operationName]))
			{
				$opClassName = "wio" . $operationName;
				if (!class_exists($opClassName))
				{
					$fileName = WI_LIB_PATH . 'operations/' . $operationName . '.class.php';
					if (file_exists($fileName))
						require_once($fileName);
					else
						throw new wiUnknownImageOperationException("Can't load '{$operationName}' operation.");
				}
				self::$cache[$operationName] = new $opClassName();
			}
			return self::$cache[$operationName];
		}
	}
?>